A built-in displacement sensor for an impact drive mechanism

Some small mobile devices often stick on a base with a magnet. In the propo sed method, a base on which a small mobile device runs has a magnetic displ acement sensor. The base made from carbon steel is divided into several par ts. A Hall device is attached to each division of the base. Because the out put of each Hall device depends on the ratio of the contact areas of the mo bile device and the divisions of the base, the device position can be measu red. An impact drive mechanism device is positioned by using this displacem ent sensor. The sensitivity and the linearity are 1.51 mm V-1 and 1.56% wit hin 3 mm, respectively. The positioning error for the distance of motion 0. 5 mm is 7 mu m in standard deviation.